The major thrust of the research is to study the impact of dietary salt on physiological processes and how that impact can be altered by the addition or deletion of hormones or other dietary components. Rats will be the animals used and the cardiovascular system is the one to which most attention will be directed. Different strains of rats will be studied since there is evidence indicating considerable variation in strain responsiveness to salt, particularly insofar as the cardiovascular system and long-term survival are concerned. Behavior, blood pressure, heart rate, respiration and body temperature will be examined during life. The chemical constitution of blood and urine, and such elements as electrolytes, plasma renin activity, urinary kallikrein will be particularly focused upon. Histologic examination of various organs and tissues will be made after sacrifice of the animals, and biopsy material may be moved during experimentation. There is evidence that excess salt ingestion has a number of deleterious effect in man and other animals, and yet it is a dietary component which is extremely abundant and widespread. These studies are primarily aimed at determining the extent to which such effect can be minimized.